The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.1108\\[1 em]x_2 &= 1.4088\\[1 em]x_3 &= 3.202 \end{aligned} $$Polynomial $ 4x^3-18x^2+16x+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.